The primary objective of the Family and Genetic Studies of Cardiovascular Disease is to identify and evaluate genetic and nongenetic determinants of cardiovascular disease and its risk factors by: 1. developing and implementing standardized methods for ascertaining and validating family histories of cardiovascular disease and related conditions; 2. examining probands, spouses, and first degree relatives from affected families and probands, spouses, and first degree relatives from a random sample of families of participants in ongoing studies using standardized methods and criteria for diagnosing cardiovascular disease, measuring selected risk factors, and collecting, analyzing, and storing blood for studies of risk factors, genetic markers, and candidate genes; 3. comparing the distributions of genetic, behavioral, physical, biochemical, and environmental risk factors, and preclinical and overt disease in the two sets of families; and 4. identifying and estimating the contributions of the specific genetic and environmental determinants and their interactions to familial clustering, risk factors, and disease. The Coordinating Center will participant in the planning and conduct of this study. It will provide administrative and scientific leadership and coordination for the development of the final protocol. It will develop or modify a data base management system and will plan, implement, and maintain distributed data entry procedures for all data collection. The Coordinating Center will check, edit, store, and analyze study date and report the results.